1. Field of Invention
The present invention relates to method and apparatus for cutting a rubber strip at a predetermined longitudinal position and for shaping the upper surfaces of the trailing end of the rubber band member and the leading end of the remaining rubber strip to have a slope with a small angle relative to the general plane of the rubber strip or rubber band member.
2. Description of Related Art
Generally, tire production involves a process wherein an unvulcanized rubber strip, e.g., a long stretch of inner liner, is cut into rubber band members each having a predetermined length. Subsequently, the rubber member is wound around a shaping drum, with its leading end laid over the trailing end and adhered thereto. When such a rubber strip is cut into band members, both the leading end and the trailing end of the rubber member are shaped to have a slope in the thickness direction with a small angle relative to the general plane, in order to ensure that the rubber member has a thickness at the joint region, which is the same as the thickness at the remaining region of the rubber member, to thereby improve the product quality in terms of uniformity of tires.
As disclosed in U.S. Pat. No. 5,293,795, for example, it has been a conventional practice to use an anvil having a flat shaping surface to place the rubber strip thereon, in combination with a press cutter/shaper having a pair of inclined shaping surfaces on the front and rear sides. The inclined shaping surfaces of the cutter/shaper have a small inclination angle relative to the shaping surface of the anvil, and intersect each other forming a boundary therebetween. In this instance, after the rubber strip has been placed on the shaping surface of the anvil, the press cutter/shaper under a heated condition is advanced toward the anvil and brought into pressure contact with the rubber strip so as to cut it at a predetermined location within the region of the boundary between the front and rear shaping surfaces. Also, while the press cutter/shaper in pressure contact with the rubber strip is advanced toward the anvil, the trailing end of the rubber member and the leading end of the remaining rubber strip are progressively deformed and shaped by the inclined shaping surfaces of the cutter/shaper on the front and rear sides, respectively, to have a cross-section having a gradually reduced thickness and forming a relatively small angle with reference to the flat shaping surface of the anvil.
The conventional procedure as mentioned above proved to be generally effective for efficiently cutting and shaping a thin strip of unvulcanized rubber into rubber band members with a desired shape. However, it has been found that such procedure may not be applicable to particular types of rubber strip, such as a stretch of inner liner in which chafers with textile cords embedded therein are applied to, and along the side edges of the inner liner. This is because the textile cords embedded in the chafers impede cutting of the rubber strip, besides that the inclined shaping surfaces of the cutter/shaper are joined to each other at an obtuse intersection angle that is typically as large as about 170° for the purpose of the desired shaping.